Al _{1− <i>x</i>} B _<i>x</i> N Ferroelectric Thin Films: Research Progress and Prospects for Engineering Applications

Al 1− x B x N (aluminum boron nitride) ferroelectric thin films are a lead‐free, CMOS‐compatible material with high thermal stability (&gt;400 °C) and robust ferroelectricity (Pr &gt;130 μC cm −2 , Ec ≈4–5 MV cm −1 ) for next‐generation electronics. Recent advances in magnetron sputtering, atomic layer deposition, and chemical vapor deposition show that boron incorporation ( x = 0.05–0.20) stabilizes the wurtzite ferroelectric phase and reduces coercive fields by 30–40% versus AlScN. Molecular beam epitaxy‐grown AlBN films exhibit ferroelectric switching, and epitaxial AlBN/GaN HEMTs with high‐κ AlBN barriers demonstrate polarization‐induced 2DEG, improved device metrics, and εr enhancement (≈7% B). Compared to conventional ferroelectrics (HfO 2 , PZT), Al 1− x B x N offers superior polarization retention (&gt;10 6 cycles at 85 °C) and tunable bandgaps (5.5–6.2 eV). Challenges include leakage current (&gt;10 −6 A cm −2 at 2 MV cm −1 ), thickness‐dependent polarization loss (&lt;50 nm), interface quality, and long‐term reliability, mitigated partly through electrode engineering (TiN, β‐Nb 2 N, Mo). Emerging applications in FeFETs, neuromorphic computing, and MEMS sensors are supported by experimental results from 25 nm heterostructures, while epitaxial Al(Sc/B)N on Mo/SiC shows promise for future devices.